Color matching?

In article , Me
wrote:

On 26/05/2016 10:29, Bill W wrote:
On Wed, 25 May 2016 13:43:57 -0700, isw wrote:

In article , Me
wrote:

On 25/05/2016 16:09, isw wrote:
Apologies if this is not the right group; seemed like a good shot to me
...

I'm trying to match some colors in an X11 environment. I pulled up the
Wikipedia article on the subject:

https://en.wikipedia.org/wiki/X11_color_names

Found some colors I liked, copied the hex values into some code I didn't
write but was tying to make look a bit better, and looked at the
resulting colors.

Which weren't the same as the color blocks in the article.

Worse, when I went probing with a "digital color meter" app that samples
pixels on the screen, the RGB values from the Wikipedia page and the
ones put up by the program I'm running were not the same either -- that
is, the RGB hex values I read for the colors were not the ones I'd typed
in, and also did not match the color blocks on the web page.

This was on a Mac, but it seems to me that whatever color inaccuracies
or "translations" the machine was doing, it should do the same thing
both times.

So, can someone enlighten me as to why the color values were different?

Isaac

Is your monitor calibrated?

I don't see how that could matter since whatever it's adjustment is, it
should be the same on the right-hand side of the screen (where the
Wikipedia page was) and the left-hand side (where the colors I was
adjusting were).

My understanding from some previous discussion here is that some
browsers also adjust the colors under some conditions. So if the
colors on the r/s were in a browser, and the l/s colors were in
another app, that could explain it.

After re-reading the OP's first post, then that's probably the answer.
Do a screen-grab or snip off the wikipedia page, past into a graphics
application like Gimp, use a colour picker to read values from that.
On W10, page viewed in Chrome (with no colour management enabled), the
values I read are exactly what they say they are.

That said, if the browser is adjusting colour in those images on the
wikipedia page - which aren't bitmap images as such but HTML coded fill
colour for cells in a table - then something is wrong with the web
browser, by design or settings.

I know better than to use screen grabs; I was using the hex values shown
alongside the colors they were "supposed* to represent. I really doubt
that the browser's "color management" (so called) was changing those.

Isaac

In article , isw
wrote:

I really doubt
that the browser's "color management" (so called) was changing those.

it was.

everything on a mac is colour managed. even finder icons.

In article ,
nospam wrote:

In article , isw
wrote:


And yes, it is calibrated, using Apple's built-in procedure.

that's not calibrated.

Not "perfectly", whatever that means, but better than not even trying.

your eyeball is not an accurate instrument.

In absolute terms, no. But as a difference comparator. not half bad. And
that is how the Apple method works.

On a scale where "zero" is totally uncalibrated, and "ten" is what you
get with a "spider" on the screen, where would you say the Apple method
comes out?

Isaac

On Wed, 25 May 2016 21:03:13 -0700, isw wrote:

In article ,
Bill W wrote:

On Wed, 25 May 2016 13:43:57 -0700, isw wrote:

In article , Me
wrote:

On 25/05/2016 16:09, isw wrote:
Apologies if this is not the right group; seemed like a good shot to me
...

I'm trying to match some colors in an X11 environment. I pulled up the
Wikipedia article on the subject:

https://en.wikipedia.org/wiki/X11_color_names

Found some colors I liked, copied the hex values into some code I didn't
write but was tying to make look a bit better, and looked at the
resulting colors.

Which weren't the same as the color blocks in the article.

Worse, when I went probing with a "digital color meter" app that samples
pixels on the screen, the RGB values from the Wikipedia page and the
ones put up by the program I'm running were not the same either -- that
is, the RGB hex values I read for the colors were not the ones I'd typed
in, and also did not match the color blocks on the web page.

This was on a Mac, but it seems to me that whatever color inaccuracies
or "translations" the machine was doing, it should do the same thing
both times.

So, can someone enlighten me as to why the color values were different?

Isaac

Is your monitor calibrated?

I don't see how that could matter since whatever it's adjustment is, it
should be the same on the right-hand side of the screen (where the
Wikipedia page was) and the left-hand side (where the colors I was
adjusting were).

My understanding from some previous discussion here is that some
browsers also adjust the colors under some conditions. So if the
colors on the r/s were in a browser, and the l/s colors were in
another app, that could explain it.

Doesn't explain why, when I measured the RGB values on the screen, they
did not match the numbers I typed in to get those very colors.

Either because it has been transformed to a different color space or
it's using an ICC profile to correct what it believes to be color
display errors. Whatever, something is changing the original data for
some reason or other.
--

Regards,

Eric Stevens

On 26/05/2016 16:05, isw wrote:
In article , Me
wrote:

On 26/05/2016 10:29, Bill W wrote:
On Wed, 25 May 2016 13:43:57 -0700, isw wrote:

In article , Me
wrote:

On 25/05/2016 16:09, isw wrote:
Apologies if this is not the right group; seemed like a good shot to me
...

I'm trying to match some colors in an X11 environment. I pulled up the
Wikipedia article on the subject:

https://en.wikipedia.org/wiki/X11_color_names

Found some colors I liked, copied the hex values into some code I didn't
write but was tying to make look a bit better, and looked at the
resulting colors.

Which weren't the same as the color blocks in the article.

Worse, when I went probing with a "digital color meter" app that samples
pixels on the screen, the RGB values from the Wikipedia page and the
ones put up by the program I'm running were not the same either -- that
is, the RGB hex values I read for the colors were not the ones I'd typed
in, and also did not match the color blocks on the web page.

This was on a Mac, but it seems to me that whatever color inaccuracies
or "translations" the machine was doing, it should do the same thing
both times.

So, can someone enlighten me as to why the color values were different?

Isaac

Is your monitor calibrated?

I don't see how that could matter since whatever it's adjustment is, it
should be the same on the right-hand side of the screen (where the
Wikipedia page was) and the left-hand side (where the colors I was
adjusting were).

My understanding from some previous discussion here is that some
browsers also adjust the colors under some conditions. So if the
colors on the r/s were in a browser, and the l/s colors were in
another app, that could explain it.

After re-reading the OP's first post, then that's probably the answer.
Do a screen-grab or snip off the wikipedia page, past into a graphics
application like Gimp, use a colour picker to read values from that.
On W10, page viewed in Chrome (with no colour management enabled), the
values I read are exactly what they say they are.

That said, if the browser is adjusting colour in those images on the
wikipedia page - which aren't bitmap images as such but HTML coded fill
colour for cells in a table - then something is wrong with the web
browser, by design or settings.

I know better than to use screen grabs; I was using the hex values shown
alongside the colors they were "supposed* to represent. I really doubt
that the browser's "color management" (so called) was changing those.

Isaac

What's wrong with using screen grabs for something like that?
I guarantee you that a screen grab on my system, copy and paste to Gimp,
then values measured with the colour-picker will be 100% accurate.
After all, it's copying actual display values in bitmap form - not some
kind of "photo".
The colour swatches on the Wikipdia page are correct - if being rendered
correctly in your web browser, which should default to sRGB.
If you've adjusted it so it doesn't render untagged images by default in
sRGB and is using aRGB or whatever, then they will be displayed
incorrectly and will measure incorrectly from a screen grab.
Image editing applications may not display exact RGB values as sRGB.
That depends on colour settings etc in the application. The
colour-picker from within the application may return the correct RGB
values as you've inputted them, but a screen grab and colour picker from
a different application will show what's actually being displayed on
screen (actually it'll just show the colour value being sent by the
computer to the monitor, which will only be close to what the monitor
shows if it's well calibrated)

In article , isw
wrote:

And yes, it is calibrated, using Apple's built-in procedure.

that's not calibrated.

Not "perfectly", whatever that means, but better than not even trying.

probably not.

the default profile is likely better.

your eyeball is not an accurate instrument.

In absolute terms, no. But as a difference comparator. not half bad. And
that is how the Apple method works.

On a scale where "zero" is totally uncalibrated, and "ten" is what you
get with a "spider" on the screen, where would you say the Apple method
comes out?

macs aren't 'uncalibrated'. they use a default profile which is
generally 'good enough' for most purposes.

eyeballing the calibration might be better (unlikely, but not
impossible) and it could also be worse. do it twice in a row and the
difference will probably be noticeable.

it also doesn't matter because even with perfect calibration (assuming
that was possible), the rgb triplets will still be modified since rgb
is device dependent.

In article ,
nospam wrote:

In article , isw
wrote:

I really doubt
that the browser's "color management" (so called) was changing those.

it was.

everything on a mac is colour managed. even finder icons.

The "those" I was referring to were the text letters and numbers
describing the color patches (i.e. #5F9EA0). No OS will reach in and
change those.

Isaac

In article ,
Eric Stevens wrote:

On Wed, 25 May 2016 21:03:13 -0700, isw wrote:

In article ,
Bill W wrote:

On Wed, 25 May 2016 13:43:57 -0700, isw wrote:

In article , Me
wrote:

On 25/05/2016 16:09, isw wrote:
Apologies if this is not the right group; seemed like a good shot to
me
...

I'm trying to match some colors in an X11 environment. I pulled up
the
Wikipedia article on the subject:

https://en.wikipedia.org/wiki/X11_color_names

Found some colors I liked, copied the hex values into some code I
didn't
write but was tying to make look a bit better, and looked at the
resulting colors.

Which weren't the same as the color blocks in the article.

Worse, when I went probing with a "digital color meter" app that
samples
pixels on the screen, the RGB values from the Wikipedia page and the
ones put up by the program I'm running were not the same either --
that
is, the RGB hex values I read for the colors were not the ones I'd
typed
in, and also did not match the color blocks on the web page.

This was on a Mac, but it seems to me that whatever color
inaccuracies
or "translations" the machine was doing, it should do the same thing
both times.

So, can someone enlighten me as to why the color values were
different?

Isaac

Is your monitor calibrated?

I don't see how that could matter since whatever it's adjustment is, it
should be the same on the right-hand side of the screen (where the
Wikipedia page was) and the left-hand side (where the colors I was
adjusting were).

My understanding from some previous discussion here is that some
browsers also adjust the colors under some conditions. So if the
colors on the r/s were in a browser, and the l/s colors were in
another app, that could explain it.

Doesn't explain why, when I measured the RGB values on the screen, they
did not match the numbers I typed in to get those very colors.

Either because it has been transformed to a different color space or
it's using an ICC profile to correct what it believes to be color
display errors. Whatever, something is changing the original data for
some reason or other.

Well, yes; obviously. I'm trying to find out what, exactly, is doing
that.

Isaac

On Thu, 26 May 2016 21:56:06 -0700, isw wrote:

In article ,
Eric Stevens wrote:

On Wed, 25 May 2016 21:03:13 -0700, isw wrote:

In article ,
Bill W wrote:

On Wed, 25 May 2016 13:43:57 -0700, isw wrote:

In article , Me
wrote:

On 25/05/2016 16:09, isw wrote:
Apologies if this is not the right group; seemed like a good shot to
me
...

I'm trying to match some colors in an X11 environment. I pulled up
the
Wikipedia article on the subject:

https://en.wikipedia.org/wiki/X11_color_names

Found some colors I liked, copied the hex values into some code I
didn't
write but was tying to make look a bit better, and looked at the
resulting colors.

Which weren't the same as the color blocks in the article.

Worse, when I went probing with a "digital color meter" app that
samples
pixels on the screen, the RGB values from the Wikipedia page and the
ones put up by the program I'm running were not the same either --
that
is, the RGB hex values I read for the colors were not the ones I'd
typed
in, and also did not match the color blocks on the web page.

This was on a Mac, but it seems to me that whatever color
inaccuracies
or "translations" the machine was doing, it should do the same thing
both times.

So, can someone enlighten me as to why the color values were
different?

Isaac

Is your monitor calibrated?

I don't see how that could matter since whatever it's adjustment is, it
should be the same on the right-hand side of the screen (where the
Wikipedia page was) and the left-hand side (where the colors I was
adjusting were).

My understanding from some previous discussion here is that some
browsers also adjust the colors under some conditions. So if the
colors on the r/s were in a browser, and the l/s colors were in
another app, that could explain it.

Doesn't explain why, when I measured the RGB values on the screen, they
did not match the numbers I typed in to get those very colors.

Either because it has been transformed to a different color space or
it's using an ICC profile to correct what it believes to be color
display errors. Whatever, something is changing the original data for
some reason or other.

Well, yes; obviously. I'm trying to find out what, exactly, is doing
that.

Try different browsers.

In article , Me
wrote:


Snipping some stuff

The colour swatches on the Wikipdia page are correct - if being rendered
correctly in your web browser, which should default to sRGB.

Yes.

If you've adjusted it so it doesn't render untagged images by default in
sRGB and is using aRGB or whatever, then they will be displayed
incorrectly and will measure incorrectly from a screen grab.

When I run the "Digital Color Meter" app over the color patches in the
browser window, it displays exactly the RGB hex values specified for
that particular patch.

So far so good.

The app I'm trying to adjust uses X11, FWIW. It reads a text document
that specifies the colors for certain objects it displays. Being an
X11/gtk environment, it understands the color "names" as well as the hex
triplets (i.e. "Cadet Blue" or "#5F9EA0" will produce the same result).

The problem is that when I enter either of those into the controlling
document and then run the app, the color that comes up on the screen, as
read by the Color Meter is *not* "#5F9EA0"; it is "#779D9F" (when the
meter is set to "Display native values"; it has other color spaces too,
but none of them produces a match either).

What I'm trying to find out is where the change to the hex values is
taking place, and why.

I have noticed similar "mismatches" between apps before, but have never
taken the time to pursue the problem.

Meanwhile, I have some "special words" for the X11/gtk people ...

Isaac